Selfie-fever has reached its pitch and now even Obama and Dave are getting involved. Two days ago, the pair took a much-commented-on shot with the Danish PM. Why all the attention? Because they were attending Nelson Mandela’s memorial service at the time. Many people have reacted strongly, declaring the selfie entirely inappropriate and disrespectful. Others have come to the leaders’ defence, claiming that a memorial service should be a time for celebration and that there’s nothing wrong with a good dose of joy. This is just the latest in a series of headlines made by the selfie phenomenon. It has been named as ‘Word of the Year 2013’ by Oxford…